Replacement of the oil within the oil pan of internal combustion engines requires periodic draining and usually, the drain hole receives a threaded plug which is manually inserted and removed.
To facilitate maintenance and reduce the time required to drain engine oil it is desirable to have a quickly operable oil drain plug. However, it is of utmost importance that any plug or valve device used be dependable and free of malfunctioning in that the inadvertent leakage of oil would quickly destroy an internal combustion engine.
Quick release or quick connect oil drain fittings of the prior art have not been as dependable and easy to use as desired, and it is an object of the invention to provide an oil drain fitting for internal combustion engines which is economical to manufacture and dependable in use, permitting the rapid draining of oil from an engine.
Another object of the invention is to provide an oil drain fitting of the quick opening type wherein a tubular valve is employed in conjunction with a spring wherein the valve is constantly biased toward the closed position and will not inadvertently open due to vibration.
An additional object of the invention is to provide a quick opening oil drain fitting for internal combustion engines whereby a drain conduit fitting may be readily attached thereto, and the attachment of the conduit fitting to the drain fitting automatically opens the drain fitting valve to initiate flow therethrough.
In the practice of the invention a tubular body includes an inner portion exteriorly threaded for reception into the conventional drain hole in the oil pan of an internal combustion engine. The outer exterior surface of the fitting is provided with means for attaching a drain conduit fitting thereto. The particular type of connection structure is not of significance with respect to the novel concepts.
The drain fitting includes an axial passage having a tubular valve reciprocal therein between open and closed positions. The inner end of the valve is closed having a head and seal ring thereon which engages with the inner end of the body valve seat to seal the interior of the valve and the body passage. The lower or outer end of the valve is open, and includes an abutment surface in the form of a flange for engagement by a probe defined on the oil drain conduit fitting wherein insertion of the conduit fitting into the body axially displaces the valve seat from the end of the body permitting oil to flow through a port defined in the valve side wall.
A compression spring interposed between the body and valve axially biases the valve toward the closed position engaging the valve seat and valve head.
A dust cap may be mounted upon the outer end of the drain fitting body, and in one embodiment of the invention the body outer end includes an annular groove for receiving radially displaceable locking balls defined on the drain conduit fitting.
To reduce costs and insure dependability and strength of components the closed end of the valve is homogeneous with the valve walls, and the closed end defines a head having a lip which holds an elastomeric seal in location. The lip portion of the head is deformable in an axial direction such that the projected diametrical dimension of the deformed lip will be less than the diameter of the fitting body passage permitting the closed end of the valve to be inserted therein. Thereupon, the lip is deformed to its normal position transverse to the length of the valve confining the elastomeric seal within its groove and permitting the valve head to be in axial alignment with the inner end of the fitting body.